Method and apparatus for producing reformed hydrocarbon and hydrogen, engine installed with fuel cell, and energy station

ABSTRACT

A reformed hydrocarbon and hydrogen are produced by: subjecting a raw hydrocarbon material to thermal catalytic cracking under hydrogen for dehydrogenation to produce a reformed hydrocarbon having a degree of unsaturation higher than that of the raw hydrocarbon material and hydrogen; introducing the reformed hydrocarbon, hydrogen and an unreacted hydrocarbon into a pressure-reducing-rising device; and reducing and then raising a pressure to facilitate further cracking of the unreacted hydrocarbon and promote liquid-gas separation in a post-step. Hydrogen can be efficiently produced, and a reformed hydrocarbon of good quality (e.g., high octane number) can be produced with suppressing generation of carbon.

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT

[0001] The present invention relates to a method and an apparatus foreffectively cracking hydrocarbon and, in particular, to a method and anapparatus for efficiently producing a reformed hydrocarbon having a highoctane number and hydrogen from a raw hydrocarbon material such as asaturated hydrocarbon, a fuel cell-mounting engine having furtherimproved energy efficiency with using the method and the apparatus, andan energy station.

[0002] In accordance with a worldwide increase of environmentalregulation, an engine using a hydrocarbon fuel has been required to savefuel consumption and lower emission of CO₂ gas in recent years. Areduction in CO₂ gas emission has the same meaning as an improvement inenergy efficiency in combustion of hydrocarbon. A fuel cell is used forthe above purpose nowadays.

[0003] The most efficient fuel for a fuel cell is hydrogen becausehydrogen easily reacts on an appropriate surface of a fuel cell at atemperature higher than room temperature to produce electricity.

[0004] Since hydrogen is a gas having the smallest molecular weight, ithas a problem of how to be produced, transported, and stored for a fuelcell.

[0005] Recently, a hybrid engine having a typical reciprocating engineand a secondary battery combined therewith has been put to a practicaluse. However, even the hybrid engine has an energy efficiency of at most30%.

[0006] Therefore, the present invention has been made in view of theaforementioned conventional problem and aims to provide a method and anapparatus capable of efficiently producing hydrogen and producing areformed hydrocarbon of good quality (high octane number, etc.) withsuppressing carbon formation, a fuel cell-mounting engine having furtherimproved energy efficiency with using the method and apparatus, and anenergy station.

SUMMARY OF THE INVENTION

[0007] According to the present invention, there is provided a methodfor producing a reformed hydrocarbon and hydrogen, comprising the stepsof:

[0008] subjecting a raw hydrocarbon material to thermal catalyticcracking under hydrogen for dehydrogenation to produce a reformedhydrocarbon having a degree of unsaturation higher than that of the rawhydrocarbon material and hydrogen,

[0009] introducing the reformed hydrocarbon, hydrogen and an unreactedhydrocarbon into a pressure-reducing-rising device, and

[0010] reducing and then raising a pressure to facilitate furthercracking of the unreacted hydrocarbon and promote liquid-gas separationin a post-step.

[0011] According to the present invention, there is further provided anapparatus for producing a reformed hydrocarbon and hydrogen, comprising:

[0012] a reactor in which a raw hydrocarbon material is subjected tothermal catalytic cracking under hydrogen for dehydrogenation to producea reformed hydrocarbon having a degree of unsaturation higher than thatof the raw hydrocarbon material and hydrogen,

[0013] a pressure-reducing-rising device for subjecting the reformedhydrocarbon, hydrogen and unreacted hydrocarbon obtained in the reactorto pressure reduction and pressure rising, and

[0014] a separator for separating the reformed hydrocarbon, hydrogen andunreacted hydrocarbon obtained in the pressure-reducing-rising deviceinto gas components composing hydrogen and liquid components composing areformed hydrocarbon and the unreacted hydrocarbon by a liquid-gasseparation operation.

[0015] According to the present invention, there is still furtherprovided a fuel cell-mounting engine comprising:

[0016] a reactor in which a raw hydrocarbon material is subjected tothermal catalytic cracking under hydrogen for dehydrogenation to producea reformed hydrocarbon having a degree of unsaturation higher than thatof the raw hydrocarbon material and hydrogen,

[0017] a pressure-reducing-rising device for subjecting the reformedhydrocarbon, hydrogen and unreacted hydrocarbon obtained in the reactorto pressure reduction and pressure rising,

[0018] a separator for separating the reformed hydrocarbon, hydrogen,and unreacted hydrocarbon obtained in the pressure-reducing-risingdevice into gas components composing hydrogen, and liquid componentscomposing a reformed hydrocarbon and the unreacted hydrocarbon by aliquid-gas separation operation,

[0019] a fuel cell using, as a fuel, the gas components composinghydrogen obtained from the separator, and

[0020] an engine using, as a fuel, the reformed hydrocarbon obtainedfrom the separator.

[0021] According to the present invention, there is yet further providedan energy station comprising:

[0022] a reactor in which a raw hydrocarbon material is subjected tothermal catalytic cracking under hydrogen for dehydrogenation to producea reformed hydrocarbon having a degree of unsaturation higher than thatof the raw hydrocarbon material and hydrogen,

[0023] a pressure-reducing-rising device for subjecting the reformedhydrocarbon, hydrogen and unreacted hydrocarbon obtained in the reactorto pressure reduction and pressure rising,

[0024] a separator for separating the reformed hydrocarbon, hydrogen andunreacted hydrocarbon obtained in the pressure-reducing-rising deviceinto gas components composing hydrogen and liquid components composing areformed hydrocarbon and the unreacted hydrocarbon by a liquid-gasseparation operation, and

[0025] a power unit for operating the pressure-reducing-rising device;

[0026] wherein the reformed hydrocarbon and the hydrogen are produced asfuels, and electric energy and thermal energy produced by the operationof the power unit are taken out with the pressure-reducing-rising devicebeing operated by the power unit.

[0027] In the present invention, it is preferable to use a reciprocatingtype of a pressure-reducing-rising device.

[0028] In addition, an energy station of the present invention mayfurther comprise a fuel cell using, as a fuel, gas components composinghydrogen obtained from the separator to take out electric energyproduced by the fuel cell.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1 is a block diagram showing a schematic configuration of anapparatus for producing a reformed hydrocarbon and hydrogen of thepresent-invention.

[0030]FIG. 2 is a block diagram showing a schematic example of aconstitution of a fuel cell-mounting engine of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention is hereinbelow described in more detail onthe basis of embodiments. However, the present invention is by no meanslimited to these embodiments.

[0032] As the basic concept of the present invention, a raw hydrocarbonmaterial (fuel) is subjected to thermal catalytic cracking underhydrogen for dehydrogenation using a reactor filled with catalyst andthe like to produce cracked products including a reformed hydrocarbonhaving an increased degree of unsaturation such as an unsaturatedhydrocarbon and hydrogen and to more effectively take out fuel of goodquality and hydrogen by a dual effect, by a pressure-reducing-risingfunction of a reciprocating engine or the like, i.e., by hydrocrackingwith an activated catalyst and quick thermal cracking under hydrogen.

[0033] For example, if a light saturated hydrocarbon is desulfurizedand, after raising pressure and temperature, subjected to thermalcatalytic cracking in a reactor containing a zeolite catalyst; hydrogencan be produced by dehydrogenation. It is possible to feed the obtainedhydrogen to a fuel cell. However, if thermally cracked components(including unreacted components) containing hydrogen obtained in thethermal cracking are fed to a reciprocating engine type cylinder device(pressure-reducing-rising device), further cracking of components in thecourse of cracking is facilitated due to pressure reduction. Then, byraising the pressure, temperature of the components further rises, whichenables further cracking and improves efficiency of gas circulation andliquid-gas separation in a post-step, and as a result, unsaturatedhydrocarbon fuel of better quality and hydrogen can be effectively takenout.

[0034] Incidentally, the reciprocating engine type cylinder device ispreferably provided with an electric discharge mechanism therein becausedehydrogenating reaction is promoted further due to radicalization ofhydrocarbon by spark discharge of electricity in a plug in the electricdischarge mechanism. Though electric discharge may be conducted at thetime of pressure reduction or pressure rising, it is more preferablyconducted at the time of pressure rising.

[0035] Therefore, according to the present invention, a fuel usable inplace of gasoline or for diesel can be produced. In the presentinvention, hydrogen is fed to a fuel cell to generate electricity usablefor an electric controller for a motor, an air-conditioner, etc., andhydrocarbon having high octane number (unsatrated) obtained besides canbe used as a fuel for the aforementioned reciprocating engine, a rotaryengine, a diesel engine, a turbine jet engine, etc., and for a fuelcell-mounting engine suitably.

[0036] In addition, the present invention gives various kinds ofadvantages due to circulated usage of hydrogen. Hydrogen can serve as aheat carrier, avoid carbon formation upon thermal catalytic cracking ofa raw hydrocarbon material, and facilitate thermal cracking reaction. Aratio of hydrogen introduced to the reactor to a raw hydrocarbonmaterial such as saturated hydrocarbon (hydrogen/hydrocarbon material)is generally 3-20 (molar ratio), and more preferably 5-10.

[0037] What is called a fuel-conversion type engine of the presentinvention becomes very efficient, particularly by being combined with afuel cell. As a further development, if, for example, propane orcyclobenzene is thermally cracked in a suitable manner, hydrogen andbenzene are obtained, which leads to an engine using completely recycledhydrogen by using only the hydrogen for a fuel cell and the benzene fora petrochemical plant or an oil-refining plant. The one requiringneither a pipeline for hydrogen nor an infrastructure becomes a hydrogenfuel cell type automobile. In this case, two kinds can be considered:One is of an alloy adsorbing and storing hydrogen type, which is crackedand supplied at gas stations; and the other is of a type having crackingin the automobile with returning benzene.

[0038] In addition, in the present invention, an energy station isprovided with an apparatus for producing a reformed hydrocarbon havingan increased degree of unsaturation (e.g., high octane number) andhydrogen, and a power unit for operating the pressure-reducing-risingdevice. In the energy station, an unsaturated hydrocarbon (reformedhydrocarbon) having a high octane number and hydrogen are taken out asfuels, and the pressure-reducing-rising device is operated by the powerunit. Electric energy and thermal energy generated by the operation canbe taken out. Such an energy station is preferably provided with a fuelcell further to be effectively used as a station (stand) for supplying afuel or electric energy to an electric automobile, a hybrid automobile,etc., as well as a reciprocating engine type automobile, which is of themain current at present.

[0039] The principle of the present invention is hereinbelow described.

[0040] In the case of using heptane (C₇H₁₆), which is a saturatedhydrocarbon, as a raw hydrocarbon material; if heptane is thermallycracked under hydrogen in a reactor filled with a catalyst and the like,toluene (C₇H₈), which is an unsaturated hydrocarbon, and hydrogen areproduced (Sekiyugakkai-shi, vol. 9, No. 1, “Successive Operation ofDehydrocyclization-Hydrogenolysis for n-Heptane” (pp. 26-27) (1966).

C₇H₁₆→C₇H₈+4H₂+ΔH₁   (1)

[0041] The reaction shown by the above equation (1) is endothermic.

[0042] On the other hand, hydrogen produced by the thermal cracking ofheptane (C₇H₁₆) can be used as a fuel for a fuel cell, and toluene(C₇H₈) can be used as a general fuel for a reciprocating engine. This isshown by the following equation:

4H₂+2O₂→4H₂O+ΔH₂   (2)

C₇H₈+9O₂→7CO₂+4H₂O+ΔH₃   (3)

[0043] Each of the reactions shown by the equation (2) and (3) isexothermic, and a heating value of each reaction is much larger incomparison with the endothermic value in the reaction shown by theequation (1); and thereby heat recovery can be easily conducted.

[0044] In standard conditions (25° C.),

[0045] the endothermic value ΔH₁=63 kJ/mole

[0046] the heating value ΔH₂=242×4=968 kJ/mole, and

[0047] ΔH₃=3948 kJ/mole.

[0048] In addition, the heating value of heptane (C₇H₁₆) is 4853kJ/mole.

[0049] A typical engine has an efficiency of about 15% during running.The effective energy of C₇H₁₆ is 4853×0.15=728 kJ/mole. On the otherhand, since toluene (C₇H₈) needs endothermic value of 63 kJ/mole, thefuel is considered to correspond to 3948−63=3885 kJ/mole. If toluene(C₇H₈) is used for an engine in a similar manner, the value becomes3885×0.15=583 kJ/mole supposing that the thermal efficiency is the same.If hydrogen is used for a fuel cell, supposing that the efficiency ofthe fuel cell is 60%, it becomes 968×0.6=581 kJ/mole; and even if about70 kJ/mole is needed for circulation energy or so, it becomes 581−70=511kJ/mole.

[0050] Therefore, in a method, an apparatus and an engine of the presentinvention, energy of (583+511)−728=366 kJ/mole can be effectively usedin comparison with a conventional engine. As to the fuel efficiency, itis increased by (366/728)×100=about 50%.

[0051] The present invention is hereinbelow described in more detail onthe basis of examples shown in the drawings.

EXAMPLE 1

[0052]FIG. 1 is a block diagram showing a schematic configuration of anapparatus for producing a reformed hydrocarbon and hydrogen of thepresent invention.

[0053] In the production apparatus, a thermal cracking reactor 2 filledwith a zeolite catalyst, a reciprocating engine type cylinder device 1,a liquid-gas separator 3, and a fuel cell 7 are disposed in this orderfrom the upstream side of a raw hydrocarbon material 6 such as asaturated hydrocarbon. When the raw hydrocarbon material 6 and recycledhydrogen 4 coming from the separator 3 are pre-heated by a heater 9 andintroduced into the thermal cracking reactor 2, the hydrocarbon materialis thermally cracked and dehydrogenated, and a reformed hydrocargonhaving an increased degree of unsaturation and hydrogen are produced.These cracked products are introduced into the reciprocating engine typecylinder device 1. In the cylinder device 1, a piston-crank mechanism 1d is driven to move a piston 1 a downward; and thereby pressure in adevice 1 b is reduced to promote cracking of unreacted hydrocarbon inthe cracked products. Then, a piston-crank mechanism 1 d is driven tomove a piston 1 a upward; and thereby pressure in a device 1 b israised, so that temperature of the unreacted hydrocarbon rises further,enabling further cracking.

[0054] The reformed hydrocarbon, hydrogen, and the unreacted hydrocarbonobtained in the cylinder device 1 are then subjected to liquid-gasseparation in the separator 3 to be separated into gas components 8composing hydrogen and liquid components 5 composing a large quantity ofreformed hydrocarbon and a small quantity of unreacted hydrocarbon.

[0055] Since a reformed hydrocarbon, for example, an unsaturatedhydrocarbon predominates in the obtained liquid components 5, the liquidcomponents 5 can be used as a fuel having a high octane value for atypical engine. On the other hand, a part of hydrogen 8 is recycled tothe reactor 2, and the rest is used as a fuel for the fuel cell 7.

EXAMPLE 2

[0056]FIG. 2 is a block diagram showing a schematic example of aconstitution of a fuel cell-mounting engine of the present invention.

[0057] The fuel 10, whose pressure is raised to 5 kg/cm²G by a fuelsupply pump P1 from a fuel tank F for storing a hydrocarbon fuelabundantly containing a saturated hydrocarbon such as a chainhydrocarbon, is mixed with the recycled hydrogen 11 at the molar ratioof 5. A temperature of the fuel 10 is raised though a heat exchanger 12and further raised to 450° C. by a heat exchanger 15 due to an engineexhaust gas emitted from an engine 14. The fuel 10 having a raisedtemperature in such a manner is introduced to a reactor 17 filled with adesulfurized catalyst or a zeolite catalyst to be cyclodehydrogenated bythermal catalytic cracking, and then introduced into a reciprocatingengine type cylinder device 18.

[0058] In the reciprocating engine type cylinder device 18, an unreactedhydrocarbon is further cracked and pressurized up to 7 kg/cm²G. Theobtained cracked products are cooled through heat exchangers 40 and 12and introduced into a separator 20 for liquid-gas separation to give ahydrogen-rich gas 21 and a reformed bottom oil (cyclic hydrocarbon) 22.A part of the hydrogen-rich gas 21 is used for a fuel cell 23, and therest is used as a recycled hydrogen 11.

[0059] The reformed bottom oil (unsaturated hydrocarbon) 22 is stored ina reformed bottom oil tank 25 and, by a reformed oil pump P2, mixed, ina mixing chamber 50, with air 26 from outside of the system withtemperature of the air 26 being raised by a turbocharger 28, and thenintroduced into an engine 14 and combusted to produce a rotationalenergy. The axis of rotation 30 is connected with a motor 33 rotating byelectricity passed through a battery 32 storing electricity producedfrom a fuel cell 23 by means of a crutch, a belt, etc.

[0060] The axis of rotation 18 a in the reciprocating engine typecylinder device 18 is connected with the axis of rotation 30. On theother hand, air 35 for a fuel cell is also heated and purified in thereciprocating engine type cylinder device 18 connected with the axis ofrotation 30 and sent to a fuel cell 23.

[0061] A raw hydrocarbon material such as a saturated hydrocarbon isconverted into a reformed hydrocarbon having an increased degree ofunsaturation (e.g., cyclic hydrocarbon) and hydrogen. The former obtainsan increased octane value and can produce rotatory power in areciprocating engine, and the latter can produce rotatory power by amotor of a fuel cell. During traveling, an improvement of efficiency byapproximately 75% could be achieved in comparison with a conventionalhybrid engine.

[0062] As described above, according to the present invention, there canbe provided a method and an apparatus capable of efficiently generatinghydrogen and producing a reformed hydrocarbon of good quality (e.g.,high octane number) with suppressing carbon formation, a fuelcell-mounting engine having further improved energy efficiency withusing the method and apparatus, and an energy station.

What is claimed is:
 1. A method for producing a reformed hydrocarbon andhydrogen, comprising the steps of: subjecting a raw hydrocarbon materialto thermal catalytic cracking under hydrogen for dehydrogenation toproduce a reformed hydrocarbon having a degree of unsaturation higherthan that of the raw hydrocarbon material and hydrogen, introducing thereformed hydrocarbon, hydrogen and an unreacted hydrocarbon into apressure-reducing-rising device, and reducing and then raising apressure to facilitate further cracking of the unreacted hydrocarbon andpromote liquid-gas separation in a post-step.
 2. A method for producinga reformed hydrocarbon and hydrogen according to claim 1, wherein thepressure-reducing-rising device is of reciprocating type.
 3. Anapparatus for producing a reformed hydrocarbon and hydrogen, comprising:a reactor in which a raw hydrocarbon material is subjected to thermalcatalytic cracking under hydrogen for dehydrogenation to produce areformed hydrocarbon having a degree of unsaturation higher than that ofthe raw hydrocarbon material and hydrogen, a pressure-reducing-risingdevice for subjecting the reformed hydrocarbon, hydrogen and unreactedhydrocarbon obtained in the reactor to pressure reduction and pressurerising, and a separator for separating the reformed hydrocarbon,hydrogen and unreacted hydrocarbon obtained in the pressurereducing-rising device into gas components composing hydrogen and liquidcomponents composing a reformed hydrocarbon and the unreactedhydrocarbon by a liquid-gas separation operation.
 4. An apparatus forproducing a reformed hydrocarbon and hydrogen according to claim 3,wherein the pressure-reducing-rising device is of reciprocating type. 5.A fuel cell-mounting engine comprising: a reactor in which a rawhydrocarbon material is subjected to thermal catalytic cracking underhydrogen for dehydrogenation to produce a reformed hydrocarbon having adegree of unsaturation higher than that of the raw hydrocarbon materialand hydrogen, a pressure-reducing-rising device for subjecting thereformed hydrocarbon, hydrogen and unreacted hydrocarbon obtained in thereactor to pressure reduction and pressure rising, a separator forseparating the reformed hydrocarbon, hydrogen and unreacted hydrocarbonobtained in the pressure-reducing-rising device into gas componentscomposing hydrogen and liquid components composing a reformedhydrocarbon and the unreacted hydrocarbon by a liquid-gas separationoperation, a fuel cell using, as a fuel, the gas components comprisinghydrogen obtained from the separator, and an engine using, as a fuel,the reformed hydrocarbon obtained from the separator.
 6. An energystation comprising: a reactor in which a raw hydrocarbon material issubjected to thermal catalytic cracking under hydrogen fordehydrogenation to produce a reformed hydrocarbon and hydrogen having adegree of unsaturation higher than that of the raw hydrocarbon material,a pressure reducing-rising device for subjecting the reformedhydrocarbon and hydrogen and unreacted hydrocarbon obtained in thereactor to pressure reduction and pressure rising, a separator forseparating the reformed hydrocarbon, hydrogen, and unreacted hydrocarbonobtained in the pressure reducing-rising device into gas componentscomposing hydrogen and liquid components composing a reformedhydrocarbon and the unreacted hydrocarbon by a liquid-gas separationoperation, and a power unit for operating the pressure-reducing-risingdevice; wherein the reformed hydrocarbon and hydrogen are taken out asfuels, and electric energy and thermal energy produced by the operationof the power unit are taken out with the pressure-reducing-rising devicebeing operated by the power unit.
 7. An energy station according toclaim 6, further comprising a fuel cell using, as a fuel, the gascomponents composing hydrogen obtained from the separator to take outelectric energy produced by the fuel cell.